Instantonic approach to triple well potential

By using a usual instanton method we obtain the energy splitting due to quantum tunneling through the triple well barrier. It is shown that the term related to the midpoint of the energy splitting in propagator is quite different from that of double well case, in that it is proportional to the algebraic average of the frequencies of the left and central wells.Comment: Revtex, 11 pages, Included one eps figur

Attack of Many Eavesdroppers via Optimal Strategy in Quantum Cryptography

We examine a situation that $n$ eavesdroppers attack the Bennett-Brassard cryptographic protocol via their own optimal and symmetric strategies. Information gain and mutual information with sender for each eavesdropper are explicitly derived. The receiver's error rate for the case of arbitrary $n$ eavesdroppers can be derived using a recursive relation. Although first eavesdropper can get mutual information without disturbance arising due to other eavesdroppers, subsequent eavesdropping generally increases the receiver's error rate. Other eavesdroppers cannot gain information on the input signal sufficiently. As a result, the information each eavesdropper gains becomes less than optimal one.Comment: 17 pages, 8 figure

Cytoprotective effects of fermented oyster extracts against oxidative stress-induced DNA damage and apoptosis through activation of the Nrf2/HO-1 signaling pathway in MC3T3-E1 osteoblasts

Osteoblast damage by oxidative stress has been recognized as a cause of bone-related disease, including osteoporosis. Recently, we reported that fermented Pacific oyster (Crassostrea gigas) extracts (FO) inhibited osteoclastogenesis and osteoporosis, while promoting osteogenesis. However, since the beneficial potential of FO on osteoblasts is not well known, in the present study, we investigated the cytoprotective effect of FO against oxidative stress in MC3T3-E1 osteoblasts. Our results demonstrated that FO inhibited hydrogen peroxide (H2O2)-induced DNA damage and cytotoxicity through the rescue of mitochondrial function by blocking abnormal ROS accumulation. FO also prevented apoptosis by suppressing loss of mitochondrial membrane potential and cytosolic release of cytochrome c, decreasing the rate of Bax/Bcl-2 expression and reducing the activity of caspase-9 and caspase-3 in H2O2-stimulated MC3T3-E1 osteoblasts, suggesting that FO protected MC3T3-E1 osteoblasts from the induction of caspase dependent- and mitochondria-mediated apoptosis by oxidative stress. In addition, FO markedly promoted the activation of nuclear factor-erythroid-2-related factor 2 (Nrf2), which was associated with the enhanced expression of heme oxygenase-1 (HO-1). However, inhibiting the expression of HO-1 by artificially blocking the expression of Nrf2 using siRNA significantly eliminated the protective effect of FO, indicating that FO activates the Nrf2/HO-1 signaling pathway in MC3T3-E1 osteoblasts to protect against oxidative stress. Based on the present data, FO is thought to be useful as a potential therapeutic agent for the inhibition of oxidative stress in osteoblasts

Activation of AMP-activated protein kinase stimulates the nuclear localization of glyceraldehyde 3-phosphate dehydrogenase in human diploid fibroblasts

In addition to its well-known glycolytic activity, GAPDH displays multiple functions, such as nuclear RNA export, DNA replication and repair, and apoptotic cell death. This functional diversity depends on its intracellular localization. In this study, we explored the signal transduction pathways involved in the nuclear translocation of GAPDH using confocal laser scanning microscopy of immunostained human diploid fibroblasts (HDFs). GAPDH was present mainly in the cytoplasm when cultured with 10% FBS. Serum depletion by culturing cells in a serum-free medium (SFM) led to a gradual accumulation of GAPDH in the nucleus, and this nuclear accumulation was reversed by the re-addition of serum or growth factors, such as PDGF and lysophosphatidic acid. The nuclear export induced by the re-addition of serum or growth factors was prevented by LY 294002 and SH-5, inhibitors of phosphoinositide 3-kinase (PI3K) and Akt/protein kinase B, respectively, suggesting an involvement of the PI3K signaling pathway in the nuclear export of GAPDH. In addition, 5-aminoimidazole-4-carboxamide-1-beta-D-ribofuranoside (AICAR), an activator of AMP-activated protein kinase (AMPK), stimulated the nuclear translocation of GAPDH and prevented serum- and growth factor-induced GAPDH export. AMPK inhibition by compound C or AMPK depletion by siRNA treatment partially prevented SFM- and AICAR-induced nuclear translocation of GAPDH. Our data suggest that the nuclear translocation of GAPDH might be regulated by the PI3K signaling pathway acting mainly as a nuclear export signal and the AMPK signaling pathway acting as a nuclear import signal.Peairs A, 2009, CLIN EXP IMMUNOL, V156, P542, DOI 10.1111/j.1365-2249.2009.03924.xChen Z, 2009, CIRC RES, V104, P496, DOI 10.1161/CIRCRESAHA.108.187567Cao C, 2008, J BIOL CHEM, V283, P28897, DOI 10.1074/jbc.M804144200Li XX, 2008, ARTERIOSCL THROM VAS, V28, P1789, DOI 10.1161/ATVBAHA.108.172452Lombardi M, 2008, J CELL BIOL, V182, P327Sen N, 2008, NAT CELL BIOL, V10, P866, DOI 10.1038/ncb1747Kim HS, 2008, J BIOL CHEM, V283, P3731, DOI 10.1074/jbc.M704432200Du ZX, 2007, ENDOCRINOLOGY, V148, P4352, DOI 10.1210/en.2006-1511Harada N, 2007, J BIOL CHEM, V282, P22651, DOI 10.1074/jbc.M610724200Goirand F, 2007, J PHYSIOL-LONDON, V581, P1163, DOI 10.1113/jphysiol.2007.132589Barbini L, 2007, MOL CELL BIOCHEM, V300, P19, DOI 10.1007/s11010-006-9341-1Hurley RL, 2006, J BIOL CHEM, V281, P36662, DOI 10.1074/jbc.M606676200Hara MR, 2006, CELL MOL NEUROBIOL, V26, P527, DOI 10.1007/s10571-006-9011-6Tisdale EJ, 2006, J BIOL CHEM, V281, P8436, DOI 10.1074/jbc.M513031200Rattan R, 2005, J BIOL CHEM, V280, P39582, DOI 10.1074/jbc.M507443200Hara MR, 2005, NAT CELL BIOL, V7, P665, DOI 10.1038/ncb1268Sirover MA, 2005, J CELL BIOCHEM, V95, P45, DOI 10.1002/jcb.20399Jones RG, 2005, MOL CELL, V18, P283, DOI 10.1016/j.molcel.2005.03.027Tisdale EJ, 2004, J BIOL CHEM, V279, P54046, DOI 10.1074/jbc.M409472200Hardie DG, 2004, J CELL SCI, V117, P5479, DOI 10.1242/jcs.01540Li J, 2004, AM J PHYSIOL-ENDOC M, V287, pE834, DOI 10.1152/ajpendo.00234.2004Cooray S, 2004, J GEN VIROL, V85, P1065, DOI 10.1099/vir.0.1977-0Brown VM, 2004, J BIOL CHEM, V279, P5984, DOI 10.1074/jbc.M307071200Tisdale EJ, 2003, J BIOL CHEM, V278, P52524, DOI 10.1074/jbc.M309343200HAWLEY SA, 2003, J BIOL, V2, P28Schmitz HD, 2003, CELL BIOL INT, V27, P511, DOI 10.1011/S1065-6995(03)00096-9Tisdale EJ, 2002, J BIOL CHEM, V277, P3334, DOI 10.1074/jbc.M109744200Schmitz HD, 2001, EUR J CELL BIOL, V80, P419Dastoor Z, 2001, J CELL SCI, V114, P1643Yeo EJ, 2000, MOL CELLS, V10, P415Stein SC, 2000, BIOCHEM J, V345, P437Sirover MA, 1999, BBA-PROTEIN STRUCT M, V1432, P159Shashidharan P, 1999, NEUROREPORT, V10, P1149Rameh LE, 1999, J BIOL CHEM, V274, P8347Sawa A, 1997, P NATL ACAD SCI USA, V94, P11669Vincent MF, 1996, BIOCHEM PHARMACOL, V52, P999Reiss N, 1996, BIOCHEM MOL BIOL INT, V38, P711CORTON JM, 1995, EUR J BIOCHEM, V229, P558KAWAMOTO RM, 1986, BIOCHEMISTRY-US, V25, P657BOYCE ST, 1983, J INVEST DERMATOL S, V81, P33

Comparison of the MicroScan, VITEK 2, and Crystal GP with 16S rRNA sequencing and MicroSeq 500 v2.0 analysis for coagulase-negative Staphylococci

BACKGROUND: Three phenotypic identification systems (MicroScan, VITEK 2, and Crystal GP) were evaluated for their accuracy to identify coagulase-negative staphylococci (CNS). A total of 120 clinical isolates confirmed to be CNS via 16S rRNA sequencing and analysis with the MicroSeq 500 v2.0 database were assessed. RESULTS: The MicroScan, VITEK 2, and Crystal GP systems correctly identified 82.5%, 87.5%, and 67.5% of the isolates, respectively. Misidentification was the main problem in MicroScan (10.8%) and Crystal GP (23.3%) systems, whereas the main problem of VITEK 2 was low-level discrimination (7.5%). CONCLUSION: None of the 3 phenotypic systems tested could accurately and reliably identify CNS at the species level. Further verifications such as biochemical testing or 16S rRNA sequencing together with analysis using a comparable database might be helpful in this regard